Many transmissive displays, such as liquid crystal displays (LCDs), include a backlight to enhance user visibility of the display under various conditions by illuminating the display. Although the overall structure and configuration may vary, a typical transmissive display includes a display and a plurality of light sources that are placed behind the display. The light sources, when appropriately energized, emit light and illuminate the display. Various types of light source backlights, for example, incandescent light, electroluminescent (EL) light, cold cathode fluorescent lamp (CCFL), hot cathode fluorescent lamp (HCFL), and light emitting diode (LED) backlights, just to name a few, have been developed and used.
Although the aforementioned displays are sufficient for displaying images under most circumstances, they may be improved. For example, in some instances, the backlight may operate in a reduced power mode for various off-nominal operating conditions, such as for thermal management purposes and/or for battery management purposes. However, because backlights are typically designed to produce substantially uniform luminance for an entire display region, each of the light sources of the backlight may be energized even though the entire display may not be needed during the reduced power mode. As a result, the display may produce images that appear dimmer than necessary.
In another example, some backlit displays may operate less efficiently in certain lighting conditions. In particular, the brightness level of the backlit display may be relatively high when used in bright sunlit conditions. Because the brightness level of the display impacts the amount of power required to operate the device and power consumption affects the length of time the device can operate on battery power, a backlit display employed in bright sunlight may have a relatively short operational time and a high electrical load placed on a vehicle power supply system. In aircraft/spacecraft applications, cooling systems may add unwanted additional weight to the vehicle.
Hence, there is a need for devices that are capable of displaying images that can operate using a minimal amount of power. Additionally, it is desirable for the device to display images that can be viewed under a variety of lighting conditions, including bright sunlight conditions. Moreover, it is desirable for the device to be relatively inexpensive and simple to fabricate. Furthermore, other desirable features and characteristics of the inventive subject matter will become apparent from the subsequent detailed description of the inventive subject matter and the appended claims, taken in conjunction with the accompanying drawings and this background of the inventive subject matter.